There are many different types of sensors on the market, with each having specific capabilities, uses, and shortcomings. One particular type of sensor that utilizes light to detect objects is known as a proximity sensor.
Proximity sensors typically consist of a light source and a corresponding photodetector. The photodetector of a proximity sensor includes a number of photosensitive pixels. Proximity sensing (e.g., detecting a presence or proximity of an object near the sensor) involves transmitting light via the light source and then receiving light that reflects off an object-to-be-detected at the photodetector. The types of applications in which proximity sensors are used include mobile communication devices, industrial equipment, manufacturing equipment, etc.
Many types of proximity sensors include a cover that separates the sensor from an open environment that is potentially dusty, dirty, and capable of damaging components of the proximity sensor. While the cover is a useful tool to protect the proximity sensor from certain dangers, the cover also presents challenges to the operation of the proximity sensor. In particular, small reflections from the cover may overwhelm the photodetector due to its close proximity to the photodetector as compared to the proximity of the object being detected.